Some airlines require that an aircraft be equipped with a temperature monitoring system which is capable of monitoring the temperature of the aircraft brake so that the pilot can be assured that the brakes are cool enough to provide a safe "rejected take-off" capability when the aircraft takes off.
The major problem in existing aircraft brake thermal sensors is the "time-lag" of the monitored or indicated temperature with respect to the actual brake temperature. This time lag is due to the face that the thermal sensors have heretofore been located away from the hottest part of the brake. Due to the location of the sensors, they tend to be affected by heat sources other than the brake, and may also be affected by contamination from the environment.